• Journal of the Korean Society of Radiology
• /
• v.16 no.3
• /
• pp.357-363
• /
• 2022

This study aims to improve the safety inspection awareness of occupational exposure and help radiation safety management by analyzing radiation exposure doses by occupational type of radiation related-workers and radiation workers. Radiation-related workers and radiation workers were classified into three occupations (radiological technologist, doctors, and nurses). A nominal risk coefficient based on ICRP 103 was used to calculate the probability of causing side effects of the lungs due to exposure doses. As a result of analyzing the exposure dose of all workers for one year, the exposure dose of radiological technologist among radiation-related workers was 1.63 ± 2.84 mSv, doctors 0.12 ± 0.22 mSv, and nurses 0.59 ± 1.08 mSv. The one-year deep dose for radiation workers was 2.44 ± 3.30 mSv for radiological technologists, 0.19 ± 0.26 mSv for doctors, and 0.12 ± 0.00 mSv for nurses. Due to this dose, the probability of causing side effects in the lungs was 1.2 per 100,000 radiological technologist, 0.096 doctors, and 0.06 nurses. In this study, it is believed that the probability of side effects on lungs by occupation of radiation exposure dose will be studied and used as useful data for radiation safety management in relation to probabilistic effects in the future.

• Journal of Biomedical Engineering Research
• /
• v.43 no.5
• /
• pp.341-352
• /
• 2022

Medical image segmentation is the most important task in radiation therapy. Especially, when segmenting medical images, the liver is one of the most difficult organs to segment because it has various shapes and is close to other organs. Therefore, automatic segmentation of the liver in computed tomography (CT) images is a difficult task. Since tumors also have low contrast in surrounding tissues, and the shape, location, size, and number of tumors vary from patient to patient, accurate tumor segmentation takes a long time. In this study, we propose a method algorithm for automatically segmenting the liver and tumor for this purpose. As an advantage of setting the boundaries of the tumor, the liver and tumor were automatically segmented from the CT image using the 2D CoordConv DeepLab V3+ model using the CoordConv layer. For tumors, only cropped liver images were used to improve accuracy. Additionally, to increase the segmentation accuracy, augmentation, preprocess, loss function, and hyperparameter were used to find optimal values. We compared the CoordConv DeepLab v3+ model using the CoordConv layer and the DeepLab V3+ model without the CoordConv layer to determine whether they affected the segmentation accuracy. The data sets used included 131 hepatic tumor segmentation (LiTS) challenge data sets (100 train sets, 16 validation sets, and 15 test sets). Additional learned data were tested using 15 clinical data from Seoul St. Mary's Hospital. The evaluation was compared with the study results learned with a two-dimensional deep learning-based model. Dice values without the CoordConv layer achieved 0.965 ± 0.01 for liver segmentation and 0.925 ± 0.04 for tumor segmentation using the LiTS data set. Results from the clinical data set achieved 0.927 ± 0.02 for liver division and 0.903 ± 0.05 for tumor division. The dice values using the CoordConv layer achieved 0.989 ± 0.02 for liver segmentation and 0.937 ± 0.07 for tumor segmentation using the LiTS data set. Results from the clinical data set achieved 0.944 ± 0.02 for liver division and 0.916 ± 0.18 for tumor division. The use of CoordConv layers improves the segmentation accuracy. The highest of the most recently published values were 0.960 and 0.749 for liver and tumor division, respectively. However, better performance was achieved with 0.989 and 0.937 results for liver and tumor, which would have been used with the algorithm proposed in this study. The algorithm proposed in this study can play a useful role in treatment planning by improving contouring accuracy and reducing time when segmentation evaluation of liver and tumor is performed. And accurate identification of liver anatomy in medical imaging applications, such as surgical planning, as well as radiotherapy, which can leverage the findings of this study, can help clinical evaluation of the risks and benefits of liver intervention.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.32 no.1
• /
• pp.21-30
• /
• 2022

Objectives: The purpose of this study is to suggest an optimal method by comparing the analysis methods of work environment measurement datasets including left-censored data where one or more measurements are below the limit of detection (LOD). Methods: A computer program was used to generate left-censored datasets for various combinations of censoring rate (1% to 90%) and sample size (30 to 300). For the analysis of the censored data, the simple substitution method (LOD/2), β-substitution method, maximum likelihood estimation (MLE) method, Bayesian method, and regression on order statistics (ROS)were all compared. Each method was used to estimate four parameters of the log-normal distribution: (1) geometric mean (GM), (2) geometric standard deviation (GSD), (3) 95th percentile (X95), and (4) arithmetic mean (AM) for the censored dataset. The performance of each method was evaluated using relative bias and relative root mean squared error (rMSE). Results: In the case of the largest sample size (n=300), when the censoring rate was less than 40%, the relative bias and rMSE were small for all five methods. When the censoring rate was large (70%, 90%), the simple substitution method was inappropriate because the relative bias was the largest, regardless of the sample size. When the sample size was small and the censoring rate was large, the Bayesian method, the β-substitution method, and the MLE method showed the smallest relative bias. Conclusions: The accuracy and precision of all methods tended to increase as the sample size was larger and the censoring rate was smaller. The simple substitution method was inappropriate when the censoring rate was high, and the β-substitution method, MLE method, and Bayesian method can be widely applied.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.32 no.3
• /
• pp.231-241
• /
• 2022

Objectives: The purpose of this study is to evaluate the input status of exposure-related information in the working environment monitoring database (WEMD) and special health examination database (SHED) for the construction of a national exposure surveillance system. Methods: The industrial and process code input status of WEMD and SHED for 21 carcinogens from 2014 to 2016 was compared. Data from workers who performed both work environment monitoring and special health examinations in 2019 and 2020 were extracted and the actual status of input of industrial and process codes was analyzed. We also investigated the cause of input errors through a focus group interview with 12 data input specialists. Results: As a result of analyzing WMED and SHED for 21 carcinogens, the five-digit industrial code matching rate was low at 53.5% and the process code matching rate was 19% or less. Among the data that simultaneously conducted work environment monitoring and special health examination in 2019 and 2020, the process code matching rate was very low at 18.1% and 5.2%, respectively. The main causes of exposure-related data input errors were the difference between the WEMD and SHED process code input systems from 2020, the number of standard process and job codes being too large, and the inefficiency of the standard code search system. Conclusions: In order to use WEMD and SHED as a national surveillance system, it is necessary to simplify the number of standard code input codes and improve the search system efficiency.

• Journal of Popular Narrative
• /
• v.27 no.2
• /
• pp.45-77
• /
• 2021

The aftermath of the COVID-19 virus continues. There are two potential fears behind the various preventive and quarantine measures. : the fear that "I may be infected" and the fear that "someone may infect me". This subconscious is built on the 'imagination of infection'. This paper attempted to analyze science fiction(SF) narratives and zombie narratives that influenced our imagination of infection. And this paper attempts to examine how SF novels and movies understand and express "infection", and how zombie narratives reveal "infection" and its horror. Mary Shelley's novel "The Last Man" revealed the paradox that the fear of an infectious disease gave humanity an opportunity for reflection. The films and showed that fear and aversion to infectious diseases can lead to riots and conflict. Zombie narrative is a genre that most dramatically expresses the horror of infection. Director Yeon Sangho's zombie trilogy, including , reveals that people around you can turn into the most dangerous source of infection. Through SF and zombie narratives, we can realize that humanity must have a humble sense of solidarity, ethics, and empathy in the face of infectious diseases. Through this narrative texts, we can realize the importance of the imagination of infection. Imagination of infection is the basis for understanding the causes and consequences of the spread of infection, the process and future prospects.

• Journal of the Korean Society of Radiology
• /
• v.16 no.7
• /
• pp.843-849
• /
• 2022

In this study, the probability of secondary carcinogenesis was analyzed by measuring the exposure dose of surrounding normal organs during radiosurgery using a gamma knife. A pediatric phantom (Model 706-G, CIRS, USA) composed of human tissue-equivalent material was set to four tumor volumes of 0.25 cm³, 0.51 cm³, 1.01 cm³, and 2.03 cm³, and the average dose was 18.4 ± 3.4 Gy. After installing the Rando phantom on the table of the gamma knife surgical equipment, the OSLD nanoDot dosimeters were placed in the right eye, left eye, thyroid, thymus gland, right lung, and left lung to measure each exposure dose. The probability of cancer occurrence due to radiation exposure of surrounding normal organs during gamma knife radiosurgery for acoustic schwannoma disease was 4.08 cancers per 100,000 at a tumor volume of 2.03 cm³. This study is expected to be used as useful data in relation to stochastic effects in the future by studying the risk of secondary radiation exposure that can occur during stereotactic radiosurgery.

• Journal of the Korean Society of Radiology
• /
• v.16 no.4
• /
• pp.471-476
• /
• 2022

The purpose of this study was to study the probability of cancer occurrence due to photoneutron dose exposure of the colon and thyroid gland, which are normal organs, in 3D CRT, IMRT 5 portals, and IMRT 9 portals, which are radiotherapy methods for prostate cancer. The total prescribed dose for prostate cancer was 6600 cGy, 220 cGy per dose, and 30 divided irradiations were applied for the total number of times. After setting up the Rando phantom on the treatment table (couch) of the medical linear accelerator used in the experiment, an optically stimulated luminescence albedo neutron dosimeter was placed on the corresponding area of the large intestine and thyroid gland of the phantom for measurement. During 3D CRT of prostate cancer, the probability of secondary cancer due to photoneutron dose to the colon and thyroid gland, which are normal organs, was 1.8 per 10,000 people. And IMRT 5 portals were 8.7 per 10,000 people, which was about 5 times larger than 3D CRT. IMRT 9 portals derived the result that there is a probability that 1.2 people per 1,000 people will develop cancer. Based on this study, the risk of secondary radiation exposure due to the dose of photoneutrons generated during radiation therapy is studied, and it is thought that it will be used as useful data for radiation protection in relation to the stochastic effect of radiation in the future.

• Korean Journal of Clinical Laboratory Science
• /
• v.54 no.3
• /
• pp.224-238
• /
• 2022

The environment and scope of work of optometric personnel in ophthalmology are unknown. We aimed to investigate these topics using an online survey. Based on the results obtained, we also make policy proposals from the perspective of clinical laboratory technologists to the University-Association-Academy. The age distribution of the study subjects was as follows; 20s (40.7%), 30s (28.4%), 40s (23.5%), and 50s (7.4%). Women constituted 56.0% of the cohort, and careers were evenly distributed from <1 to ≥15 years. We found optometric personnel had high levels of work-related stress, frequent occupational diseases, and that their duties were wide in scope. More manpower is needed to reduce work stress and improve work satisfaction. Clinical laboratory technologists held more senior positions at 48% compared to others and the occupational distribution was closely related to the senior occupation (P<0.001). Clinical laboratory technologists were responsible for about 30 types of eye examinations, and the most frequently performed examination was the refraction test; anomaloscopic examinations took the most time (27 minutes). Taken together, clinical laboratory technologists perform various eye exams. Given the importance of clinical laboratory technologists in optometry, a multifaceted effort is required at the University-Association-Academy.

• Therapeutic Science for Rehabilitation
• /
• v.10 no.4
• /
• pp.53-63
• /
• 2021

Objective : This study aimed to develop a Korean version of the Flow State Scale for Occupational Task (K-FSSOT), to measure the level of a flow experience of a subject in occupational therapy activities. Methods : To develop a measure of K-FSSOT, validity and reliability were verified through a systematic development process. The validity was verified by calculating the content validity index (CVI) through the content validity of 10 occupational therapists and a question-and-answer survey of 20 patients. Reliability was verified by investigating the internal consistency and examination-re-test reliability of 33 patients. Results : The item-CVI for each question in the content feasibility study was .90 to 1.00, and the scale-CVI, which is the average of the whole item, was found to be appropriate at .97. The verification of reliability indicated that the intrinsic value of the entire question was high at .855, and the test-retest reliability value was high at .894 (p<.01), showing a high correlation, and very high reliability. Conclusion : K-FSSOT could be used as a useful tool to measure the level of a flow experience of the target in performing occupational therapy activities for occupational therapists concerned about the participation and flow experience of the target.

• Parasites, Hosts and Diseases
• /
• v.60 no.1
• /
• pp.39-43
• /
• 2022

Plasmodium vivax exhibits dormant liver-stage parasites, called hypnozoites, which can cause relapse of malaria. The only drug currently used for eliminating hypnozoites is primaquine. The antimalarial properties of primaquine are dependent on the production of oxidized metabolites by the cytochrome P450 isoenzyme 2D6 (CYP2D6). Reduced primaquine metabolism may be related to P. vivax relapses. We describe a case of 4 episodes of recurrence of vivax malaria in a patient with decreased CYP2D6 function. The patient was 52-year-old male with body weight of 52 kg. He received total gastrectomy and splenectomy 7 months before the first episode and was under chemotherapy for the gastric cancer. The first episode occurred in March 2019 and each episode had intervals of 34, 41, and 97 days, respectively. At the first and second episodes, primaquine was administered as 15 mg for 14 days. The primaquine dose was increased with 30 mg for 14 days at the third and fourth episodes. Seven gene sequences of P. vivax were analyzed and revealed totally identical for all the 4 samples. The CYP2D6 genotype was analyzed and intermediate metabolizer phenotype with decreased function was identified.